1. Field of the Invention
The present invention relates to a vehicular lamp in which a light source unit, which includes at least an LED used as a light source and a reflector that reflects the light from the light source in a predetermined direction, is attached to a heat sink and accommodated in a lamp chamber, and more particularly to a vehicular lamp in which a power supply circuit board with an LED chip is attached via an attachment to a heat sink at a predetermined position.
2. Related Art
Recently, development of a vehicular headlamp that uses an LED as a light source has been promoted. In a headlamp of this type, a light source unit, which includes an LED used as a light source and an optical element (e.g., a reflector or a projection lens) that directs the light emitted from the LED in a predetermined direction, is attached integrally to a heat sink used as a member for supporting the light source unit, and accommodated in a lamp chamber.
As described in, for example, Patent Document 1, the LED is fixed to a heat sink at a predetermined position, by placing a frame-shaped flat plate attachment, which has an open portion in its center portion, over a power supply circuit board with an LED chip (hereinafter referred to as “LED module”) from above so that the LED chip is surrounded by the attachment, and then screwing the attachment onto the heat sink (from the front surface side of the attachment).
When the LED is used as a light source, it is desired that the light emitted from the LED be efficiently utilized because the LED emits a smaller amount of light than an incandescent bulb and a discharge bulb.    [Patent Document 1] Japanese Patent Application Laid-Open (Kokai) No. 2008-153080 (Paragraphs 0006, 0010, FIG. 2)